Interspecific Differences in Growth and Nitrogen Uptake among Crotalaria species

[摘要] The interspecific differences in germination, root nodule formation, dry matter production and nitrogen uptake were evaluated among Crotalaria species for the introduction as new green manure legumes. The germination progressed smoothly in C juncea and C spectabilis, but physical scarification was neccessary in C. pallida. In the field experiment, C. juncea had a high dry weight and a great nitrogen content at the early growing stage, but a drastic defoliation and a high C-N ratio were found at the late growing stage. C. pallida grew slowly at the early stage, but a high nitrogen content and an adequate C-N ratio for decomposition were found at the late growing stage. C. spectablilis showed intermediate traits in dry matter production and nitrogen uptake. In the root-box experiment, the distribution patterns of root systems and root nodules varied among the three species. C. juncea had greater root growth and nodulation compared with two other species at 35 days after sowing. When the three species are introduced to various cropping systems, these traits should be considered for choice as green manures.

[学科分类] 农业科学（综合）

[关键词] C-N ratio;乾物生産;Crotalaria;クロタラリア;Dry matter production;C-N率;Green manure crop;窒素吸収;Nitrogen fixation;窒素固定;Nitrogen uptake;緑肥作物